474267-90-8Relevant academic research and scientific papers
Towards understanding monomer coordination in atom transfer radical polymerization: Synthesis of [CuI(PMDETA)(π-M)][BPh4] (M = methyl acrylate, styrene, 1-octene, and methyl methacrylate) and structural studies by FT-IR and 1H NMR spectroscopy and X-ray crystallography
Braunecker, Wade A.,Pintauer, Tomislav,Tsarevsky, Nicolay V.,Kickelbick, Guido,Matyjaszewski, Krzysztof
, p. 916 - 924 (2005)
CuI complexes of the form [CuI(PMDETA)(π-M)] [BPh4] (where PMDETA = N,N,N′,N″,N″- pentamethyldiethylenetriamine, and M = vinyl monomer) were synthesized and isolated from solution as crystals with methyl acrylate (MA), styrene (Sty), and 1-octene (Oct). The interaction of the C=C double bond of the vinyl monomer with CuI was characterized via FT-IR and 1H NMR spectroscopy and single crystal X-ray crystallography. A fourth complex with methyl methacrylate (MMA) was synthesized and characterized spectroscopically, but no crystals suitable for X-ray structure analysis could be obtained. In all complexes, PMDETA acts as a tridentate ligand, while the pseudotetrahedral coordination geometry around CuI is completed by a π-interaction with the C=C double bond of M in the presence of a non-coordinating counter-ion. A decrease in C=C IR stretching frequencies of Δν(C=C) = -110, -80, -109, and -127 cm-1 for complexes with MA, Sty, Oct, and MMA, respectively, was observed upon coordination. No significant change in C=C bond length was seen in the crystal structure for complexes with MA and Oct while a slight lengthening was observed for the Sty complex. The upfield shift of the vinyl proton resonances indicated the presence of significant π-back-bonding.
